Stereotype backing powder or filling



. UNITED STATES PATENT OFFICE.

THOMAS MANGAN,OF OARTI-IAGE, ASSIGNOR OF ONE-HALF TO IVILLIAM WV. PEASE,OF ELMWOOD PLACE, OHIO.

STEREO'T-"YPE BACKING POWDER OR FILLING.

$PECIFIGATION forming part of Letters Patent No. 453,343, dated June 2,1891.

Application filed December 18,1890. Serial No. 375,122. (No specimens.)

To all whom/it may concern.-

Be it known that I, THOMAS MANGAN, a citizen of the United States,residing at Carthage, in the county of Hamilton and State of Ohio, haveinvented certain new and useful Improvements in Stereotype BackingPowder or Filling, of which the following is a full, clear, and exactdescription.

My invention relates to an improved backing or filling'powder to be usedin the preparation of stereotype matrices for the purpose ofre-enforcing and stiffening the same; and its novelty will behereinafter set forth, and specifically pointed out in the claim.

The process of preparing stereotype-matrices is substantially asfollows: The previously-moistened soft and spongy paper is placed on thetype and forced into all of the spaces and interstices thereof by abrush or other proper instrument. The filling-powder or other material,of which there are several kinds now in use, is then applied to fill upall the cavities and interstices of the paper and a backing of paper orstraw board is laid on, pressed down, and the whole dried, after whichthe matrix is removed, andis ready for use in casting thestereotype-plate. The great desiderata in fillings of this character arethat they shall dry quickly, so as to require the least possible time inthe manufacture of the matrices, and that they shall have the requisiteconsistency and hardness to withstand the weight of the stereotype metalwhen poured, so as to give clear and sharp impressions. Most of thefillings now in use are faulty in one or the other or both of the aboverequirements, and my invention seeks to remedy thesedefects bysubstantially a new filling material in place of those before used. Tothat end I prepare a powder composed of about forty-three parts ofmarble-dust and about seven parts of ordinary wheat flour or other flourcontaining a glutinous substance, and with this mixture in a dry state Imake the filling in the usual manner.

iVhile other proportions of the same ingredients may be used, I havefound the proportions named to give the most satisfactory results, bothas to quick drying and requisite hardness to withstand the pouring ofthe stereotype metal and to give sharp prints from the stereotypedplate.

Matrices made in this way may be used a number of times, if desired.

I am aware that clay, plaster-of-paris, and lime combined with aglutinous substance have been before used for fillings, but thesesubstances were more or less imperfect in one or the other or both ofthe respects above pointed-out and not equal in point of resistance andhardness to marble-dust and flour used in substantially the proportionswhich I have indicated.

Having thus fully described my invention, 1 claim- As an article ofmanufacture, a filling or backing for stereotype-matrices composed of orcontaining as essential ingredients marbledust and flour, substantiallyas and for the purpose described.

THOMAS MANGAN.

Witnesses:

J. THOMSON ORoss, G. S. WENTwoRTH.

